Regulation of the lac operon in E. coli (see Chapter 16) and regulation of the GAL system in yeast are analogous in that they both serve to adapt cells to growth on different carbon sources. However, the transcriptional changes are accomplished very differently. Consider the conceptual similarities and differences as you address the following.

Compare and contrast the roles of the lac operon inducer in bacteria and Gal3p in eukaryotes in the regulation of their respective systems.